Process of producing artificial-silk filaments by drawing



Ap 10, 192&

K. GRUNERT PROCESS 01" PRODUCING ARTIFICIAL SILK FILAMENTS BY DRAWING Filed Oct; 4. 1926 Patented Apr. 10, 1928.

UNITED STATES 1,665,453 PATENT OFFICE.

KURT GRUNERT, F TURIN, ITALY.

PROCESS OF PRODUCING ARTIFICIAL-SILK FILAMENTS BY DRAWING.

Application filed October 4, 1926, Serial No. 139,509, and in Germany October 8, 1925.

This invention relates to a new process for the production of artificial silk filaments by drawing. I am aware that processes for the production of artificial silk from cuprammonium cellulose solutions are known by means of a spinning apparatus employing a vertically arranged and freely suspended column of liquid to permit a free and frictionless passage of the filament bunches forming, while the drawing and precipitation of the individual filaments is caused by the precipitant forming the suspended column of liquid. The speed of fiow of this procipitant within the spinning cylinder must be much less than the speed of the free fall.

To accomplish this the column of liquid within the spinning cylinder was subjected to siphon action and the speed and quantity of the precipitant adjusted within the limits required by altering the difference of level betwien inlet and outlet or by throttling the sup y.

owever, this process ,is disadvantageous in so far as the suspended'column of liquid is subjected to the action of a vacuum which during the spinning process causes the air contained in the precipitant to form bubbles and settle underneath the spinning shower. In this manner the formation of filaments is interfered with to such an extent that the liquid often breaks under the action of the vacuum and the contents of the spinning device run out so that alongcr interruption of work becomes necessary.

The invention eliminates the suspended column of liquid and the drawbacks connected therewith by placing the liquid moving within the spinning device under atmospheric pressure while the speed of its movement is adjusted by a second flow of liquid which has a retarding effect. It is possible to use precipitants which have not been. deprived of air. To facilitate the supply of the second liquid a device has been provided for it at the outlet of the precipitant, and the regulation of speed of the precipitant can be influenced either by the powerof the kinetic or potential energy of the second flow of liquid.

The illustrations show one form of the invention in section Fig.1 showing an assembly of the various elements and Fig. 2

showin the lower end of the spinning funnel with t 9 connecting container on a larger scale.

1 is the spinning shower emitting the s inning solution which enters the spinning unnel 2. 3 is a vessel containing the precipitant entering the spinning funnel 2 through a small tube providedwith a regulating cock. 4 is a second vessel for the reception of a second liquid which through a piece of pipe provided with cock and hose enters thecontainer 5 arranged at the lower end of the spinning funnel.

During the spinning process proper the liquid leaving the container 4 acts contrary to the precipitant emitted by the funnel 2, and the speed of the precipitant will be regulated according to the kinetic or potential energy of the liquid leaving the container 4. After their union both liquids are caught in the basin 6 while the filament 7 can be wound up.

I claim 1. The herein described process of producing artificial silk filaments, especially from cuprammonium cellulose solutions, by drawing, which consists in causing the solution, on leaving a spinneret, to entera spinning funnel with a precipitating liquid, the spinning funnel having an open top, keeping the precipitating liqu1d and threads under atmospheric pressure therein, and regulating the outlet velocity of the precipitating liquid by the counteraction of a second liquid meeting the first liquid at the point, where it comes from the funnel whereupon both liquids jointly flow into a basin and the filament is taken off.

2.- The herein described process of producing artificial silk filaments, especially from cuprammonium cellulose solutions, by drawing, which consists in causing the solution, on leaving the spinneret, to enter a spinning funnel wlth a precipitating liquid, the spinning funnel havin an open top, keeping the precipitating liquid and the threads under atmospheric pressure therein and regulating the velocity of discharge from the said funnel by the kinetic or potential energy, of a second liquid meeting the first liquid at its KURT GRUNEBT. 

